He accepted a scholarship to play at Boise State University where he focused on playing cornerback. Before leaving school as a junior, in his career he started 38 of the 39 games, had 152 tackles, 3.5 sacks, five forced fumbles. In 2007 he recorded a school single-season and career record with four blocked kicks (field goals and extra points).

After posting the fourth fastest 40-yard dash (4.32 seconds) at the scouting combine and falling in the 2008 NFL Draft because of probable character problems, the Dallas Cowboys traded that year's fifth and seventh round draft choices to the Seattle Seahawks, in order to move up in the fifth round to draft him. From the start as a rookie, he became the team's nickelback.

In 2011, Scandrick signed a six-year contract with the Cowboys worth $28.2 million and $10 million in guarantees. In 2013, he passed Morris Claiborne on the depth chart and became the starter at right cornerback after the third game of the season. On December 13, he signed an additional two-year contract extension.[2]

On August 11, 2014, the NFL announced that Scandrick would be suspended for the first four games of the season for the usage of performance-enhancing drugs.[3] Although it was confirmed that he tested positive for MDMA, during his suspension the league revised its drug policy and his punishment was reduced to two games, by changing his violation from performance enhancing to substance abuse.[4] He made his debut in week 3 against the St. Louis Rams, surpassing Claiborne on the depth chart at right cornerback. During the season, he continued his emergence into an above average cornerback capable of playing both on the outside or inside, known as the "slot."